Guys,
I have been flying TP 4S 1P 3900 mah Pro Lite 4G packs for about 9 months. I have 5 packs and rotate them as the days flying unfolds. I use a TP 610C with balancer each time I charge and have only charged them at 1.5C rate. Two of the packs are the older ones have seemed to puff they only have 8 cycles on one and 12 on the other. My typical draw is 34 amps, for a flight time of 5 min 20 sec. The plastic covering seems to balloon out but the cell seems to be flat. I'm not sure what is causing this or if the cells are about to go? Also not sure why it is doing this with just a low number of cycles. Any ideas?

Best,             DennisT

Wynn,
Normal battery temp at the end of the flight is about 105F ish on a 90F day, can always pick them up, motor is a little warmer around 120F. I fly every week and normally charge them the night before, if I miss a week they will stay at the 30% level until charged. When I check the pack it seems that the plastic wrapper is what is puffed. How much puffing is OK? What causes this and should I send them back to TP? The pack still takes a balanced charge (within 0.02) and performs solid to the end of the flight.

Best,                DennisT